Messages in this thread | | | Subject | Re: Make ipconfig.c work as a loadable module. | From | (Eric W. Biederman) | Date | 07 Mar 2003 19:03:24 -0700 |
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Bogdan Costescu <bogdan.costescu@iwr.uni-heidelberg.de> writes:
> On Fri, 7 Mar 2003, Russell King wrote: > > > Which version is overly bloated? > > Which version is huge? > > Which version is compact? > > ... and the size is not important only because we want to make everything > smaller, but because of how it's commonly used (at least in the clustering > world from which I come): > > the mainboard BIOS or NIC PROC contains PXE/DHCP client; data is > transferred through UDP, with very poor (if any) congestion control.
Only because the implementations suck. See etherboot.
> Congestion control means here both extreme situations: if packets don't > arrive to the client, it might not ask again, ask only a limited number of > times or give up after some timeout; if the server has some faster NIC to > be able to handle more such requests, it might also send too fast for a > single client which might drop packets. In some cases, if such situation > occurs, the client just blocks there printing an error message on the > console, without trying to restart the whole process and the only way to > make it do something is to press the Reset button or plug in a keyboard... > When you have tens or hundreds of such nodes, it's not a pleasure !
But this is all before the kernel is loaded. Having booted a 1000 node cluster with TFTP and DHCP. From a single host with even being in the same town, I think I have some room to talk.
> Booting a bunch of such nodes would become problematic if they need > to transfer more data (=initrd) to start the kernel and so network booting > would become less reliable. Please note that I'm not saying "ipconfig has > to stay" - just that any solution should not dramatically increase the > size of data transferred before the jump to kernel code.
Right. But I would suggest fixing your NBP (what PXE load) which must be < 64K anyway if you have noticeable reliability problems. Not that I even suggest using PXE for production use anyway. But sometimes you are stuck with what you can do.
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